Float controlled valve



19, 1965 J. RUDELICK FLOAT CONTROLLED VALVE Jan.

3 Sheets-Sheet 1 Filed June 23 1961 Jan. 19, 1965 J. RUDELICK FLOATCONTROLLED VALVE Filed June 23. 1961 3 sh t -sheet 2 Jan. 19, 1965 J.RUDELICK 3,166,091

FLOAT CONTROLLED VALVE Filed June 2:. 1961 3 Sheets-Sheet z /J 2121 RunZwk United States Patent 0,

, 3,166,691 FLOAT CONTRGLLED VALVE John Rudelick, Milwaukee, Wisassignor to Brunei Corporation, Milwaukee, Wis, a corporation ofWisconsin Filed June 23, 1961, Ser. No. 119,133 2 Ciaims. (Cl. 137-391)I tion are commonly used as so-called brine valves in auto-.

matic water softeners, where they are mounted in the brine vessel andcontrol the level to which fresh water is-filled into the vessel and thelevel to which brine is withdrawn therefrom; In such water softeners thebrine vessel is of course separate from the softening tank that containsthe bed of ion exchange material. When the ion exchange material is tobe regenerated, brine is transferred from the brine vessel to thesoftening tank, usually by means of an injector through which a streamof fresh water flows to the softening tank and by which brine is drawnfrom the brine tank into the fresh water stream. Thesuct-ion effectproduced by the flow of fresh water 1 through-the injector opens thebrine valve, allowing brine to flow out Oflth brine vessel through thevalve until the brine in the vessel falls to a predetermined low level,and then the brine valve is closed by its float actuator tb step furtherwithdrawal of brine from the vessel and thus pre vent eduction' of airinto the stream of freshwater which mam Patented, Jan. 19,; 11965actuated to either of a pair of closed positions by the pres- V sure ofliquid flowing through the valve body, ratherthan by thebuoyancy and/ orweight of the float actuator, and wherein means under the control of thefloat actuator releasably holds the valve element out of its closedpositions so long as the float actuator is between defined limits ofmotion but permits the vvalve element to move to one or the other of itsclosed positions,.depending upon the direction of liquid flow throughthe valve body, when the float actuator reaches limits of ;'motion. I

Another object ofthis invention is to provide aninex pensive anddependable flo'at actuated valve for water softener briners and the likewhich can be readily mounted in a brine vessel and can be adjustedtoclose when liquid in the vessel reaches any one of a number ofdifferent continues to flow to the water softening tank. In a subsequentphase of the regeneration cycle fresh water is filled into the brinevessel through the brine valve, to provide for the formation of brinefor the next regeneration, and when liquid in the brine vessel rises toa predetermined level the brine valve is automatically closed by itsfloat actuator to terminate filling.

' Recently-there has come into general use in automatic water softenersystems a type of brine vessel which may be referred to as the-dry saltplatform type, wherein the salt store is supported on a foraminousshelf-like supporting member, or platform, that is spaced above thebottom of the vessel. The water level in the brine vessel is normallymaintained only very slightly above the upper surface of the platform,sothat substantially only the bottom surface of the salt store is incontact with water, and the major portion of the salt store thus remainsdry. With a dry salt storage platform type of briner it is importantthat the brine'valve be capable of very accurate eration of the floatactuator for the valve. 1

minimum levels, and with which such adjustment can be readilyaccomplished merely by setting the float at different positions alongthe length of the float It is.

also an objectof this invention to provide such avalve whereinadjustment of the float to controlthe' minimum. liquid level for -valveclosure does not alfectthe upper level at which the valve c1oses,'sothat the valve: of'this' invention is particularly suitable for -drysalt platform briners, which mustalways be filled to the same' liquidlevel, regardless of the amount of brine that is removed 'at eachwithdrawal. 1

Still another object of this invention resides inthef provision of a drysalt platform'type'of briner having a' float actuated valve by which thefilling of liquid'into the brine ve'ssel and its withdrawal therefrom iscon trolled, and wherein the foraminous member on which the salt storeis, supported does not interfere witli'op It is a further specificobjectof this invention to provide a float -actuated valve of thecharacter described." having in its body a very simple movable valveelement that comprises a pair of oppositely facing resilient disclikevalve members coaxially carried-on a stemQwhich 1 is slidably guided inthe valve body and which projects to the exterior thereof.

Still another specific object of this invention is to an i vide a floatactuated valve of the, character described which attains all of theabove stated objectives and:

which, moreover, is capable of providing a throttled actuator motion.

partment and a valve compartment, and Whereinfresh Water entering thevessel throughthe brine valve is incontrol of the level to which liquidis filled into the brine vessel, andthat the valve close promptly andpositively as soon as liquid in the vessel reaches the bottom of thesalt store, since otherwise an excessively large portion of the'saltstore would be immersed in water and the advantages of the dry saltplatform type of briner would be lost.

With the foregoing in mind, it is a general object of this invention toprovide a float actuated valve of the type. through which liquid isfilled into and Withdrawn from avessel, and which closes toterminate-filling and, emptying of the vessel when liquid thereinreaches predetermined maximum and minimum levels, respectively; whichvalve is particularlywell adapted for use as a brine valve in dry saltplatform type briners for water softening systems by troduced into thevalve compartment, whence it makes its way into the brine compartmentthrough a port or volume of water has entered the vessel. Hence itfollows that it is another object. of ,this invention, related, to. theobjective of providing a float actuated valve ca.- I pable of affordinga substantially throttled. or restricted flow of liquid, to provide abrine valve which willnot'l close until the full required volume ofwater'has beenw filled into the brine ves'selin which it isinstalledgbut which'is capable of permittingsubstantiallyunrestrictedflow of fresh water-,jduring the initial stages0f filling:

of the vessel vso as to expedite, the filling process.

With the above and other objects injview which will appear as thedescription proceeds this. invention resides] in the novel construction,combination'and arrangement, r

one or the other of its definedholes in the supporting member. V I u 1 uIn this case the brine'vessel doesnot hav'e'the usual uprightpartition,"but;instead the platform has, its medial derstood that suchchanges in the precise embodiment of the'h ereindisclosed invention maybe'madeas comewithin the scope of the claims.

"FIG RE 1 is a fragmentary'side elevational view a "a brine' vesselhaving a-valve'of this invention therein, T withportions of the vesseland the valvebroken away.

and shown in section;

FIGURE 2'Sl'lOWS the valve of this invention per se, partly in sideelevation andpa'rtly in section, with the float armrin a'position in.which theva'lveisopen;

FIGURE: 3 is aview similar to FIGURE 2 but show 7 ing thevalve in aclosed position inwhi'ch it prevents withdrawa'l of liquid from a vesselin whichit is installed, FIGURE 4' is across sectional view ofthe'valve, taken on the plane of the lin m FIGURE 1; 7,

FIGURE 5 is a fragmentary top view of the ,valve;

- FIGURE 6 isa fragmentary top view'of amodified form of the valve shownin FIGURES 1-5; and

; FIGUREV is a vertical sectional view. of a further l 1 Referrmg now tothe accompanying. drawings, the

modified embodiment of the valve off this .invehtion.

numeraldesignates generally a waterfsoftener brine vessel of the1drysaltplatform type, having aforaminousplatform l spaced a substantialdistance above. its hot tom,'upon whicha salt store7 is adapted to rest.The platform comprises a, foraminous shelf-like horizontal supportingmember 8 of metal, 'plastic jor other rigid ma-- 7 teria'l, whichcarriesa relativelyfine mesh screen 9 that prevents 1 small salt particles fromfallin'g through the portion 'boWed'upwardly-to define arr-invertedU-shaped tunnel or channel 10 beneath which the valvell of thisihvention and its float actuator '12 are 'accoimnodated; The valveyll,which serves. to controlthefilling of fresh I water into the vesselandthelwithd'rawalof-b'rine there- I from,sis' mounted in the-sidewall-of the vessel, and pro 7 While the;.' valve could be mountedat any elevation above the. bottom of the'ves'se'l, cohsistent'withproperop'eration of its float actuator 12, it is shown in thepresent'case as mounted jec'tsjforwardlyinto the valve compartment.

in the neighborhood of. the desiredhighest liquid level in the vessel.To allow. liquid 'to bewithdrawn from the vesselwhenthe level'of suchliguid' falls below the eleva-- tion of the valve'body 13 a flexibletube 14 extends down -Wardly from the valve body into the vessel, nearlyto the bottom of the vessel; The tunnel 10 of course allows the floatactuator to swing upto a substantially horizontal i positionas liquid in'thevesselrises to its maximum level, 1

without interference frornthe platform.

In "general the valve'll comprisesrin addition to the valve body 13 andthe float actuator 12, a movable valve element 35 and a cam-likecontrol. element or abutment member In which comprises a part of thelloat actuator andprovidesa connectionbetween said actuator and thevalve element. The valve'el'emen't comprises a stem 17 to which is fixed'a. coaxial jhead consistingfof a' rigid reinforcing disc 19' and a pairo f resilient sealing discs 29 and 2G, oneat each axial side oftherigid disc. The valve element isgmounted in'the bodyffor axialsliding motion with its head inside the valve; bodyfand with a portion21 ofjitsstemsfl-atall times projecting forwardly fronrthe valve body.Opposing shoulder means 22 and 22': at axially spaced apart locations onthe projecting position of the float actuator.

comprising a front bodyportion 23 and a rear body portion 24, whichcooperate to define a'passage 25 througn.

the valve body that includes a chamber 26 in which the" head of thevalve elementis situated. Coaxial flanges 27 around the body'partsprovide for their connection and also providerfor securernent of thevalve to a suitable annular mounting pad 28 or the like on the brinevessel 5, as by means of bolts 29.

The passage 25through the rear of the'body in acoaxial rear port 30 andat the front of the body in a downwardly opening frontportdl at theunderside of thebody, to which the flexible tube 14 is connected. Asuitable 'duct' 32 communicates the rear port 353 with another part of'theapparatus in whichthe valve is-insta1led; W'henthe'valve element isin 'anopen position, with its discs 26 and 20" intermediate the seats 3:3 and 33, liquid can flow through the valve chamberz from one of theports to the other by reason of the fact thatthe diameter of saidchamberis substantially larger than that of the discs comprising theheadof thevalve element;

To guide the valve elementjfor axial back and forth.

j motioninthe valve body' itss'tem 17 is slidably received in a coaxialspider portion 34 which maybe formed integrally with the rear valvebodymember, and in acoaxial bore 35 through the front body member, openingfrom the hollow interior thereof. .'A suitable seal 36 around i .thestein prevents air from leaking into the valve body through the boreSSwhen the level of liquid in the vessel isbelowtheYmouth of 'saidz'bore;but this seal-fcanbe;

omittedif the valve is so mounted in the vessel atga'lltirri 'es below.the level of liquid therein; 1 up The projecting front end portion 21 oflthe ivalv" elei rnent '1 is; disposed betweeii andipar allel to ripenof.

. forwardly/projecting bifurcations'37 fonthefront hody memberth'atffsupport a pin or trunnion 33 on whichthe float actuator ispivotedfor up and down swinging motion and which extends through slot tl inth'efroht 'e'nd por-" tion of the stem. The float arm "comprises a rod ortube {EZhaving its inner'e'nd secured to the control element 16and'having a buoyant fioati tfi securedfon its-outer end portion. Theheat "43 is axially adiustable along the.

length of the rod or tube '42 andfis held in any desii'etl positionofsuch adjustment asb'y meansof resilient-"fries tionwashers whichsnuglyembrace the rod. Such axial adjustment of the float provides forcontrol of the r'ninimum liquid level in the vessel at which closure ofthe. valve takes place, as hereinafter explained.

I a V port on 21 of thewalve stem cooperate with the control element l6in a manner described hereinafter to control "the POlilQIliOfthenvalve=element in accordance with the The control element orabutmentmember 16 has identic'allyshapedcam-like bifurcations 44 whichstraddle the projecting portion 21 of the valve stem and are confinedbetween the bifurcations 37 on the front of thevalve may:

a The pin or trunnion 38of course extends through the bi-f furcations ofthe control'element to mount it for pivotal motion by which the floatactuator, is allowed to swing up and down. The peripheral surfaces: ofthe two camlike bifurcations of the control elementproyide abutment:surfaces which cooperate with the shoulderls Z Z and 22"611 the valvestem to provide, in effect; a releasable latch con- I nection betweenthe valve element and the float actuator;

The shoulders 22 and 22 can be provided by pins fixed in the valve stemand; projecting toopposite sides thereof, and it will be "observed thatthe. trunnion pin 38, in extending through the slot 40 in the'valvestem, prevents the latter frorn rotating out of a position in whichtheaxes of a shoulder pins 22 and '22? are parallelto that" of thetrunn'ion pin. Q

- The periphery of each of the bifurcations on: the abut-. mer t memberprovides a pair of large radius lower abutment surfaces 46 and-46',which-maybe coaxial with the trunnion 38 and which terminate. abruptlyat substantially radially inwardly extending surfaces 47 and 47'. Asmaller radius edgeportioh .48 extends around the top of eachbifurcation of the control element, from the inner ends oftheradialsurfaces 47 and 47'.

the valve body termin ates at When the float arm is in positions (asshown in FIGURE 2), corresponding to liquid levels in the vessel whichare between the highest and lowest desired levels, one or the other ofthe shoulders 22 and 22 on the valve stem engages an arcuate portion 46or 46' on the periphery of the abutment member'lrrby which the valveelement is held in an intermediate position, with the discs 21 andspaced'from both of their cooperating seats. Thus FIGURE 2 illustratesthe conditions which obtain when liquid is being drawn out of the vesselin which the valve is mounted, flowing from the front port 31 to therear port 39 in the valve body. The liquid acts upon the valve element15 to urge it rearwardly, toward engagement of the disc 29 on the valveelement with its seat 33, but unt l the liquid in the vessel falls tothe desired minimum level, the arcuate cam-like surface 46 on theabutment member will be en-v gaged by the shoulder 22 on the stem torestrain the valve element against movement to its seated position.

If the flow of liquid through the valve body were reversed, with liquidbeing filled into the vessel through the valve, sucl1 liquid flow wouldof course urge the valve eleand the float arm swings down to the angleillustrated in FIGURE 3, corresponding to the minimum desired liquidlevel, the cam-like arcuate surface 46' on the abutment member 16rotates away from engagement withthe shoulder 22' on the valve stem,allowing said shoulder to move any of a range of intermediate member asthe valve element moves in response to liquid pressure to its closedposition in which the disc 29 engages the rear seat 33. ment will remainin that closed position so long as pressure in the duct 32 is lower thanthat in the tube 14, and that the pressure of the liquid itself, ratherthan the weight of the float actuator, is relied upon to maintaingoodsealing engagement between the valve element and its seat.

When pressure in the duct. 32 subsequently increases, at thecommencement of filling of the vessel, the valve element is of courseforced oif of its rear seat 33 and urged forwardly toward the front seat33 by the liquid flowing toward the vessel, but the rear shoulder 22 onthe valve stem now engages the arcuate abutment surface as on thecontrol element to hold' the valve eiement in its intermediate openposition. It might be noted at this point that the opposing faces of theshoulders 22 and 22 on the valve stem are spaced apart by a distancesomewhat greater than the combined radii of the arcuate sur faces 46 andon the abutment member, so that when the rear shoulder 22 engages thecam-like arcuate surface 4-5, the front shoulder 22 willbe wellclear ofits adjacent arcuate surface 46 and out of engagement with the.

It will be observed that the valve ele-' valve body, as shown in FIGURE1, the arcuate surface 45 on the abutment member is rotated out ofengagement with the rear shoulder 22 on the valve stem, and saidshoulder moves forwardly along the radial surface47 on the controlmember asthe Valve element moves into engagement with its front seat 33'in response to the pressure of incoming liquid, thereby terminatingfilling of the vessel.

With the valve mounted in the position shown in FIG- URE l,substantially at the maximum desired liquid level, the float arm willalways be in a substantially horizontal position when liquid in thevessel reaches said level, re.-

' defining pin 15% is confined in the" arcuate medial portion gardlessof the position of the float 43 along the length of the rod ortube 42,and consequently any change in the in which provision should desirablybe made for adjustment of the volume of brine draw-off at eachregenenation to accommodate "the conditions of water hardness, frequencyof regeneration, etc., f of the particular water softener installation.a v 1 It will be seen from the foregoingdescription of the operation ofthe valve that when the float actuator is in its intermediate range ofpositions the spacing ofreach resilient disc 29' andZil' on theivalvehead from its adjacent seat 33 and 33 is governed by the radius ofthearcuate abutment surface 46 and 46 which holds the valve 7 elementunseated. It follows that flow of liquid through the valve in eitherdirection can be throttledby suitably decreasing the radius of theproper arcuate abutment surface 46 or 46. Thus it is'desirable insomecases to permit rapid flow of liquid into the vessel during the initialstages of filling, but to effect a decreasing flow rate as liquid in thevessel approaches the desired maximum; level; and under thesecircumstances the abutment surface 46 would have a radius whichdecreased circumferentially' toward the surface 47, thus allowing'thevalve element to approach its seat as the float arm rises.

vFEGURE 6' illustrates another means of obtaining regulation of'rate offlow of fluid through the valve-.. The

lshoulder 22 on the valve stem is provided by .a pin or screw 5b whichis rotatably seated in the stem and which has an eccentric projectingportion that defines theshoul der. As the pin sets rotated, the positionof its projecting Obviously either or both of the shoulders 22 and'22'on the valve stem can be made adjustable in this manner, and; suchadjustable shoulders can cooperate with arcuate surfaces on the abutmentmember which are of non-uniform radius as well as those having aconstant radius.

In the embodiment of the invention} illustrated in FIG- URE 7 thestenrl17 of the valve element; carries a single pin which providesoppositely facing abutment surfaces 122 and 122 thereon, and whichcooperates with the opposite edge portions of a slot 52 in the cam-likecontrol element or abutment member 116. As in the' 7 case ofthepreviously described embodiment of the valve, the abutment member 116 ismounted on a pin or trunnion 138 cariid bybifurcations 137 on the valvebody, and the rod 142 comprising the outer portion of the float arm issecured to the abutment member to swing the same about the trunnion axisas the float 43 rises and V through the medial'portion of its range, theshoulder 133'. As the floatarm swings up to its maximum'liquid levelposition, shown in full lines, the notch portion 147' of the slot 52 isbrought into alignment with the pin 150,

allowing the valve 'element to engage the seat 133' and prevent furtherflow of liquid through the valve and into As the float arm swingseitherupwardlyiordownwardly thevessel in which the valveismounted. Whenthefloat 7 arm swings downto' the minimum liquid level, thejnotchportion 147 of the slot 52 aligns with the pin 150, allowing the valveelement to engage its other seat 133 to prevent furtherwithdrawal ofliquid ofrom. the vessel in which i the valve is mounted.

The valve illustrated in FIGURE 7 is well adapted' for mounting with theaxis of its stem'117 upright, and it is therefore better suited than thevalve of FIGURES 1-6 to mounting in a relativelyfnarrow vessel or tank;It:

may be somewhat more expensive to produce, however,

because of the necessity for forming the slot 52 in the a abutmentmember 116; r w

From the foregoing description; taken together with i theaccompanyingdrawings it will be apparent that this invention provides afloatiactuated':valve which particularly well suitedfor installation indry salt platform typ'e'brinersj by reasonof the fact, that it-permitsfad-' justment of the minimum liquid level'in a vessel in which, itis'installed,-for 'regulation of the amount of liquid re-' moved fromthe vessel at each Withdrawal, but provides for maintenance or aninvariablepredetermined maxia mum level of liquid in the vessel,irrespective of the minimum liquid level for which the valve may be adjusted. It', Wll l be further apparent that in the'valve of thisinventions the valve element is moved to and held in itsseated'positiori-in' response to the pressure of liquid flowing, throughthe valve b dy, rather-than. by the weight and buoyancy of the fioatactuator, thus afford-r o 30 a thar'theyalve of this, inventioncanefie'ct throttled new of liquid into orout of a vessel, eitherthroughthe en} the range of emotion of its float actuator or through anying a very positive valve action. It will also befseen desired partthereof, 7 i 1, What is claimed as my invention is: 1

l. A valve through which liquid can be both filled-into and withdrawnfrom a vessel, and which terminatesoflow;

of liquid to and from the vessel when liquid therein respectively, saidvalve compris'ingz,

reachesf predetermined maximum and minimum levels,-

- 7 1 ('1) a passage therethrough' opening to"s paced apart'externalports in the valve body,.to and from each of which liquid can flow,

(2) a'va'lve chamber'provided by an intermediate portion-of saidpassage,

(3) annular valve seats 1n said passage that 0p 7 pose one'another andfaceintothe valve chami v ber; (B) a stem member in the valve bodyextending 7 through the valve chamber and" coaXially through the valveseats and'having a'portion projecting to;

, the exterior or the valve body; I

' V (C) a valve'element coaxially fixed on said stern mernher,intermediate; the ends-thereoi'and disposed in said valve chamber, saidvalve element having a pair of-surfa'ces that oppose andare'engageablewith said valve seats; i

(.D means in the valve body'fslidably supporting the *stem' member ataxially opposite sides of the valve f chamberto provide forliquidpressure responsive movement of the valve elementfin opposite-axialdirections, to each ofta pair'of-closed' positions at 'which: one ofsaid. surfaces engages its opposing valvese'at, andto Ian intermediateopen-position in which both'of said surfaces are spaced from theiropposing seats;

"(E) a float'rnember mounted for movement in'opposite directionsrelative 'to'the valve body'between' defined upper and lowerlirnits; anda (F) a pair of cooperating latch elements', each connected' with one vof said members for. movement 1 therewith,comprisingcooperatingabutments on the float member and on *saidportionof thestem memthat areengaged Wheneverthefloat member'is between its limits of motion toprovide an interlock by which the valve element is held in itsintermedie ate position, against flow responsive movementto ra close'clposition,'bu t which are disengaged in con- 7 sequence of movement ofthefioat member to one or" its limitsof motion to release the stemmember for liquid pressure responsive movement of the valve element to aclosed position. 7 v

2. A valve through whichrliquid can be-both filled into and withdrawnfrom a vessel, and which terminates flow of liquid to andfrom the-vesselwhen liquid therein reaches predetermined maximum and minimum levels,respectively, Said valve comprising;

r t. (A) .a valve body having sureresponsive movement of the valveelement in oppositeaxial directions, tozeachof a'f'pair of closedpositions at which one of said valve surfaces engages itsopposin seat,and to an intermediate open, position in which'both of said surfaces arespaced from their opposing seats;

(D) a float arm member mounted for swinging up and, down motionbetweendefined limits about an axis fixed with respect to the valvebody; (E) a float'on said float artnmember; (F) cam follower'means onsaid portion of the stem of the valve member; and a (G) a cooperatingcam connected to the float arm member to swing therewith and havingarcuate cam surfaces facing in opposite directions axially of the stemwhich" are engageable-by the cam' follower means when the float arrnjisbetween its limits of motion, andwhich are of such-.arcuate" length asto be disenga ed fromthe cant follower means when 7 J the float armreaches each of its limits of; motion to'freerthe valveelement for fluidpressure responsive movement" into engagement with one of the valveseats. 1 1

References Qited in the file of this patent UNITED STATES PATENTS2,556,872 Deters June 12, 1951 2,710,018 were; June 7, 1955 r 2,814,306Ponsar' V Nov; 26, 1957, 2,820,419 Albertson ]an. 21, 1 958 L FOREIGNPATENTS Canada Dec. 6, 1955 valve surfaces that face toward, said valveseats and r

1. A VALVE THROUGH WHICH LIQUID CAN BE BOTH FILLED INTO AND WITHDRAWNFROM A VESSEL, AND WHICH TERMINATES FLOW OF LIQUID TO AND FROM THEVESSEL WHEN LIQUID THEREIN REACHES PREDETERMINED MAXIMUM AND MINIMUMLEVELS, RESPECTIVELY, SAID VALVE COMPRISING: (A) A VALVE BODY HAVING (1)A PASSAGE THERETHROUGH OPENING TO SPACED APART EXTERNAL PORTS IN THEVALVE BODY, TO AND FROM EACH OF WHICH LIQUID CAN FLOW, (2) A VALVECHAMBER PROVIDED BY AN INTERMEDIATE PORTION OF SAID PASSAGE, (3) ANNULARVALVE SEATS IN SAID PASSAGE THAT OPPOSE ONE ANOTHER AND FACE INTO THEVALVE CHAMBER; (B) A STEM MEMBER IN THE VALVE BODY EXTENDING THROUGH THEVALVE CHAMBER AND COAXIALLY THROUGH THE VALVE SEATS AND HAVING A PORTIONPROJECTING TO THE EXTERIOR OF THE VALVE BODY; (C) A VALVE ELEMENTCOAXIALLY FIXED ON SAID STEM MEMBER, INTERMEDIATE THE ENDS THEREOF, ANDDISPOSED IN SAID VALVE CHAMBER, SAID VALVE ELEMENT HAVING A PAIR OFSURFACES THAT OPPOSE AND ARE ENGAGEABLE WITH SAID VALVE SEATS; (D) MEANSIN THE VALVE BODY SLIDABLY SUPPORTING THE STEM MEMBER AT AXIALLYOPPOSITE SIDES OF THE VALVE CHAMBER TO PROVIDE FOR LIQUID PRESSURERESPONSIVE MOVEMENT OF THE VALVE ELEMENT IN OPPOSITE AXIAL DIRECTIONS,TO EACH OF A PAIR OF CLOSED POSITIONS AT WHICH ONE OF SAID SURFACESENGAGES ITS OPPOSING VALVE SEAT, AND TO AN INTERMEDIATE OPEN POSITION INWHICH BOTH OF SAID SURFACES ARE SPACED FROM THEIR OPPOSING SEATS; (E) AFLOAT MEMBER MOUNTED FOR MOVEMENT IN OPPOSITE DIRECTIONS RELATIVE TO THEVALVE BODY BETWEEN DEFINED UPPER AND LOWER LIMITS; AND (F) A PAIR OFCOOPERATING LATCH ELEMENTS, EACH CONNECTED WITH ONE OF SAID MEMBERS FORMOVEMENT THEREWITH, COMPRISING COOPERATING ABUTMENTS ON THE FLOAT MEMBERAND ON SAID PORTION OF THE STEM MEMTHAT ARE ENGAGED WHENEVER THE FLOATMEMBER IS BETWEEN ITS LIMITS OF MOTION TO PROVIDE AN INTERLOCK BY WHICHTHE VALVE ELEMENT IS HELD IN ITS INTERMEDIATE POSITION, AGAINST FLOWRESPONSIVE MOVEMENT TO A CLOSED POSITION, BUT WHICH ARE DISENGAGED INCOMSEQUENCE OF MOVEMENT OF THE FLOAT MEMBER TO ONE OT ITS LIMITS OFMOTION TO RELEASE THE STEM MEMBER FOR LIQUID PRESSURE RESPONSIVEMOVEMENT OF THE VALVE ELEMENT TO A CLOSED POSITION.